我有三张桌子;
表结构是：
医生表：+-----------+----------+---------+----------------+----------------+
| doctor_id | phone_no | room_no | date_qualified | date_appointed |
+-----------+----------+---------+----------------+----------------+
| 50 | 1234 | 1 | 1963-09-01 | 1991-05-10 |
| 51 | 1235 | 2 | 1973-09-12 | 1991-05-10 |
| 52 | 1236 | 3 | 1990-10-02 | 1993-04-01 |
| 53 | 1237 | 4 | 1965-06-30 | 1994-03-01 |
+-----------+----------+---------+----------------+----------------+
人员表
+-----------+----------+-----------+---------------+------+
| person_id | initials | last_name | date_of_birth | sex |
+-----------+----------+-----------+---------------+------+
| 100 | T | Williams | 1972-01-12 | m |
| 101 | J | Garcia | 1981-03-18 | f |
| 102 | W | Fisher | 1950-10-22 | m |
| 103 | K | Waldon | 1942-06-01 | m |
| 104 | P | Timms | 1928-06-03 | m |
| 105 | A | Dryden | 1944-06-23 | m |
| 106 | F | Fogg | 1955-10-16 | f |
| 150 | T | Saj | 1994-06-17 | m |
| 50 | A | Cameron | 1937-04-04 | m |
| 51 | B | Finlay | 1948-12-01 | m |
| 52 | C | King | 1965-06-06 | f |
| 53 | D | Waldon | 1938-07-08 | f |
+-----------+----------+-----------+---------------+------+
约会表
+-----------+------------+------------+-----------+---------------+
| doctor_id | patient_id | appt_date | appt_time | appt_duration |
+-----------+------------+------------+-----------+---------------+
| 50 | 100 | 1994-08-10 | 10:00:00 | 10 |
| 50 | 100 | 1994-08-16 | 10:50:00 | 10 |
| 50 | 102 | 1994-08-21 | 11:20:00 | 20 |
| 50 | 103 | 1994-08-10 | 10:10:00 | 10 |
| 50 | 104 | 1994-08-10 | 10:20:00 | 20 |
| 52 | 102 | 1994-08-10 | 10:00:00 | 10 |
| 52 | 105 | 1994-08-10 | 10:10:00 | 10 |
| 52 | 150 | 2014-03-10 | 12:00:00 | 15 |
| 53 | 106 | 1994-08-10 | 11:30:00 | 10 |
+-----------+------------+------------+-----------+---------------+
我需要创建一个查询来为每位医生制作一份约会清单，包括医生的姓名，患者的姓名以及约会的日期时间和持续时间。结果应按医生的姓名和约会日期/时间排序。
我尝试了以下代码：
select person.last_name, person.initials, person.last_name, appointment.appt_date, appointment.appt_time, appointment.appt_duration -> from doctor inner join appointment on doctor.doctor_id = appointment.doctor_id -> inner join person on person.person_id = appointment.patient_id -> order by person.initials, person.last_name, appointment.appt_date, appointment.appt_time;
我得到了以下结果，其中没有医生的名字，而且只有一个，还有姓氏的2列。
+-----------+----------+-----------+------------+-----------+---------------+
| last_name | initials | last_name | appt_date | appt_time | appt_duration |
+-----------+----------+-----------+------------+-----------+---------------+
| Dryden | A | Dryden | 1994-08-10 | 10:10:00 | 10 |
| Fogg | F | Fogg | 1994-08-10 | 11:30:00 | 10 |
| Waldon | K | Waldon | 1994-08-10 | 10:10:00 | 10 |
| Timms | P | Timms | 1994-08-10 | 10:20:00 | 20 |
| Saj | T | Saj | 2014-03-10 | 12:00:00 | 15 |
| Williams | T | Williams | 1994-08-10 | 10:00:00 | 10 |
| Williams | T | Williams | 1994-08-16 | 10:50:00 | 10 |
| Fisher | W | Fisher | 1994-08-10 | 10:00:00 | 10 |
| Fisher | W | Fisher | 1994-08-21 | 11:20:00 | 20 |
+-----------+----------+-----------+------------+-----------+---------------+
答案 0 :(得分：1)
姓氏来了2次，因为你选择了2次
select person.last_name, <------ here
person.initials, person.last_name, <---- here
appointment.appt_date,
appointment.appt_time,
appointment.appt_duration
from doctor
inner join appointment on doctor.doctor_id = appointment.doctor_id
inner join person on person.person_id = appointment.patient_id
order by
person.initials,
person.last_name,
appointment.appt_date,
appointment.appt_time;
删除其中一个
由于您没有选择医生名称，因此未显示医生名称。你的医生桌子没有你所显示的名字。检查数据库是否有名称，然后在查询中添加。
根据您的要求检查以下内容是否有帮助!!
select person.last_name,
person.initials,
d.last_name as DoctorName,
appointment.appt_date,
appointment.appt_time,
appointment.appt_duration
from appointment
inner join doctor on doctor.doctor_id = appointment.doctor_id
left join person on person.person_id = appointment.patient_id
left join
(
select * from person
)d
on d.person_id = appointment.doctor_id
order by
person.initials,
person.last_name,
appointment.appt_date,
appointment.appt_time;